1. Field of the Invention
The present invention relates to a computer-controlled interlocking system for a railway installation which is divided into subsidiary sections, in which, for the control of the roadway elements assigned to the respective subsidiary sections, special computers (section computers) are provided which are fail-safe in terms of signaling technology.
2. Description of the Prior Art
An electronic interlocking system of the type set forth above is generally known, for example, from the brochure F-516 of Siemens AG entitled "All Clear for the Future: Electronic Interlocking" in which a railway installation which is to be controlled is divided into a plurality of adjacent subsidiary sections (Section 1, Section 2) which extend parallel to the main direction of travel, and each subsidiary section is controlled by way of an individual central unit (section computer) which monitors the interlocking function.
In a compound computer system, each unit is planned and programmed in accordance with its function and a processing peripheral assigned thereto. In the case of the electronic interlocking system based on the section computer principle, it would therefore be necessary to plan individually all the computers within a system. This planning and programming of each individual computer is necessary both during the construction of the installation and also, for example, on the occasion of each alteration. If the track system is to be altered, it is necessary to intervene in the hardware and software of the individual computers, i.e. changes must be made in the data supply of the read only memories (ROMs) of all the computers. This can only be carried out by the manufacturer; therefore, the expense for amending the memory contents is considerable. Since, for reasons of ensuring reliability in railway signaling technology, a change in the data in the memories of the individual section computers also necessitates an extensive checking of the memory contents and for this purpose access must be provided to the individual section computers, it is extremely problematic to restore the operation of a modular interlocking system of this kind following a change in the system configuration or a change in the division of the system into individual subsidiary sections.
The use of a special computer which is fail-safe in terms of signaling technology to control the master data of a railway installation is already known from the German published application No. 31 27 363, fully incorporated herein by this reference. In the interlocking system disclosed therein, which is controlled by a plurality of individual computers, the individual computers must fulfill different functions within the control sequence. Therefore, for example, there is a computer for the command handling, a computer for the route requirement, a computer for the formation of routes, a computer for the dissolution of routes, and, amongst others, a computer for the status control. This computer obviously serves mainly for documentation purposes, but at least it does not serve to convey system-specific data to the other computers within the computer system in a loading phase. If it were desired to transfer the function-divided computer system disclosed in the aforementioned German published application to a computer system which is assigned to individual subsidiary sections of an installation, this would mean that in place of a central unit for the control of a subsidiary section a plurality of function classified computer units would need to be provided for each subsidiary sections. This would mean that each subsidiary section would have to be assigned an individual computer for the status characterization which would involve precisely the same disadvantages set forth above.